This is adapted, only slightly, from Carole Walter's Great Cakes.
1 stick unsalted butter, melted
3 T flour
3 T cornstarch
Two eight-ounce packages Philadelphia cream cheese
15-ounces ricotta cheese
1 pint sour cream
1 1/2 cups sugar
Juice of one lemon
zest of one lemon
1 T vanilla extract
For the crust:
10 graham crackers or 1 1/2 cups crumbs
2 T sugar
1/3 cup melted unsalted butter
Preheat oven to 325°
Make the crust:
Butter a 9-inch springform pan.
Process graham crackers in a food processor until they are fine crumbs. Add sugar and pulse to combine. Add melted butter and pulse just to blend.
Empty crumbs into prepared pan and press onto bottom and up along sides. I use a measuring cup to press the crumbs into the edge of the pan. Refrigerate crust until ready to fill.
Make the cake filling:
Melt butter over low heat. Reserve.
Sift together flour and cornstarch and reserve.
Using a stand mixer with paddle attachment, cream the cream cheese for 2-3 minutes until softened. Add the ricotta and mix until smooth, about 3-4 minutes. Scrape sides and bottom of bowl to make sure the cream cheese is well-blended.
Add the sugar in three parts, over about a minute of mixing time. Stop mixer to scrape sides of bowl as necessary.
Add the eggs, one at a time, mixing well between additions.
Add the flour/constarch, vanilla, lemon juice and zest and mix well.
Add the melted butter and sour cream and mix just to combine, about 30 seconds.
Pour the batter into the prepared pan and bake for one hour.
At the end of the hour, turn off the heat (without opening the oven door) and let cake sit another hour.
Remove from oven and cool to room temperature. Refrigerate until ready to serve.
An hour before serving, remove cake from fridge and disengage spring. Cake should release easily. If not, run a knife around the edge.
If you like, brush the surface with raspberry jam and top with raspberries or strawberries. You can make a light glaze for the berries by warming seedless jam with some sugar syrup and painting it on the tops of the berries.